Electrical apparatus



p 1954 G. J. KNUDSON 2,675,448

ELECTRICAL APPARATUS Filed April 7, 1951 IN V EN TOR.

AT TO RN EY- Patented Apr. 13 1954 UNITED STATES FF I CE ELECTRICAL APPARATUS Gilmer.;l.-.Knudson, GuilforrL-N. i2, assignor-to Bendix Aviation-Corporation, New York, N.- 2., a corporation of ;Delaware Application April7, 1951; Serial No.219g881 7 Claims. 1,

This invention relates 0 electrical apparatus and more particularly to movable means *for transmitting electrical energy from one stationam" part toanother through rotating or movable parts;

One of the objects of the invention is to provide novel'means adapted for use in 'such devices as ignition distributors fortransmitting electrical energy from a stationary part to a plurality of stationary contacts-in sequence.

Another object of the invention is to provide a novel rotor-construction for use in an ignition distributor "or the like, said rotor being of simple construction, inexpensive' tc manufacture, and reliable inoperationwhile having only a relative- 1y fewfparts.

Still another object of the invention is to provide'in'an-electrical apparatus of the above -char acter novel simplified means for continuously urging a pair ofcurrentcarrying brushe of car-- bon or like material on a rotating part into operative position and formaintaining said brushes under a relatively uniform pressure during use.

-A further object is to provide in an ignition distributor rotor or the like-novel means for resilientlybiasing pairs of cooperating current conducting brushes into operative position, said means functioning also to electrically connect said brushes to each other and to hold the same in assembled relation and against movement out of'the'rotor.

Still another object is to provide apparatus of the above character which *maybe readily and easily assembled and disassembled thereby reducing the manufacturing cost and facilitating replacement of Worn or defective parts.

A still further object is to provide a novelly constructed distributor rotor wherein the movable parts have a freedom of movement relative to each other which substantially eliminates any danger of the parts becoming wedged or bound against proper movementduring operation.

The above and further objects and novel features of the invention will more fully appear'from the following detail description when the same is read in connection with the accompanying drawings. It is to be expressly understood, however, 'that the drawings are for the purpose of 11- lustration only and are notintended-as a definition of the limits of the invention.

In the drawings, wherein like "reference character refer to like parts throughout the several views,

Fig. 1 isa none elevation view of an ignition distributor rotor constructed in accordance with the present-invention Fig; :2 is assectionalview oftsaid rotor, the section: being taken substantially-on line 2--2 of Rig: 1;

3 is a detail 'view, partly'rin section'sh-owing the constmction'iof asliding brush acontact member;

Fig. 4 15 an end view "of the current conducting bifush'illustrated in Fig. 3, the view being taken from :the bottom inthe latterfigure;

Fig.5 isa 'rdetailview showing the bridge memher through. which yielda'ble pressure is applied to a pair of :contactcarrying brushes;

Fig. *6 is an end view of the bridge member illustrated in Fig. 5:;1:and

.Figs. 7 and 8 are sectional side and bottom end views, respectively, of aguide or bushing in which a said contact'brushoperates.

In the accompanying drawings'th'e present invention is illustrated, byway of exampleas being embodied distributor rotor of the type empioyed in connection with a distributor unit which is adaptedifor usemitheignition system of a 'multi-cylinderinternal combustion engine and particularly in the type wherein relatively low voltage current :is distributed from a common source to a plurality of spark plug circuit in sequence. In the specific. lform shown, the novel rotor-construction consists primarily of a block or'body- I'll made of metal or other suitably strong material. The rotor .is equipped: with two: pairs of current conducting brushes H, t2 and 13, 14 adjacent opposite ends thereof for continuously picking up electrical current from a source thereof and conducting the same to the spark plugs in thereng-ine "cylinders in a'manner which is well understood in-the art. Ln the particular constructionfillustrated the brushes l2, l3 are each adapted topick .up electrical current from a stationaryring connected witha source of electrical energy and the brushes I I and M, which are electrically connected with brushes :12 and [3, respeclovely in. a manner 'tobe hereinafter specifically described, "are adapted to engage concentric rings .of'sspaced arcuate contacts which may be connect-ed With'the spark plugs in'the cylinders of an engine.

Block or body it of the rotor may be made of any suitable rnateri al, but in the interest of strength-and small dimensions, the same is preferably madeof light metal. A central opening I 6 having askeyway I l is provided for mounting rotor it one rotatableashaft for rotation therewith.

Each of the current carrying contact brushes I i, i2, wand i t is of substantially the same or identi'cail ccnstruction and accordingly, only one will be described with specific reference toFigs.

3 and 4. In the form specifically shown, each brush comprises a body 18 of carbon or equivalent electrically conductive material, said body being cylindrical except that opposed sides may be provided with flats IQ for a purpose to be hereinafter mentioned. If desired, the flats I9 may be tangent to a circle having the same center as bearing 16. One end of body I8 is provided with a threaded axial recess 19a into which is threaded a cap or terminal member 20. The enlarged head portion of terminal member 20 comprises a cylindrical portion 2| which engages the end of body [8 and is of somewhat greater diameter to thereby overhang body [8 to provide an external shoulder 22. Said head portion also comprises a cylindrical tip portion or pin 23 which is connected to cylindrical portion 2| by a portion 24 which has an external segmental sphere-like contour. Member 29 may be made of any suitable electrically conductive material, but metal is preferred. If desired, the brush [8, '20 may be made from a single block of electrical- 1y conductive material which is suitable for the use to which the device is to be put.

As best seen in Fig. 2. the rotor block or body is provided with an axially extending opening or passage 26 for each of the current conducting brushes. A tubular bushing or insert of insulating material 21 is mounted in each of the openings 26 for supporting the brushes and for insulating the same from the metallic rotor body. If the rotor body is made of insulating material, the bushings 21 are not necessary. If desired, each bushing 21 may be provided with a projection or key 28 (Fig. 7) on the side thereof for engaging a corresponding groove in body I!) to prevent rotation of the bushing relative to the rotor body. Bushings 21 have axial openings therethrough which are shaped to conform with and slidably receive the contact brushes. The noncylindrical openings through bushings 2? and the corresponding shape of the brushes prevents turning of the brushes in the bushings. In installations wherein turning of the brushes about their own axes is not undesirable, the brushes and the bores of the bushings may be cylindrical. The current carrying brushes project beyond one face of rotor III for engagement with stationary rings, segments or the like of conductive material, and movement of each brush in one direction relative to the rotor body is limited by the engagement of shoulder 22 on terminal member with the end of bushing 21.

Novel means are provided for yieldably retaining the brushes in rotor I0 when the latter is disassembled from an ignition distributor unit or the like and for yieldably resisting reciprocating movement of said brushes during operation of the rotor in a distributor unit or other comparable device. In the form shown, said means comprises a bridge or yoke 30 formed of a relatively stiff bar or rod of electrically conductive material. As shown, yoke 30 is made of an elongated piece of sheet metal which is transversely curved to increase the rigidity thereof "and for effecting suitable contact thereof with the curved or sphere-like surfaces 24 of caps 20 on the conducting brushes. Near the ends of yoke 30 the same is provided with elongated slots 3| which receive the tip ends 23 of the contact carrying brushes. These pin and slot connections permit limited movement of the yoke at right angles to the axis of movement of the brushes, thus allowing a desired freedom of relative movement of the moving parts.

At its center, bridge or yoke 30 has a portion thereof sheared and pressed downwardly to form a loop 32. The upper end or coil spring 33 is shaped to form a hook 34 which may be readily engaged with or disengaged from the loop 32. Spring 33 is preferably enclosed by an insulating bushing 35 mounted in rotor body In between brushes H and [2. The lower or end turn of spring 33 is enlarged to engage a shoulder within bushing 35 so that when the parts are assembled with the spring under tension, the biasing force or" the spring will be transmitted through yoke 39 to the'contact brushes II and I2. This arrangement of the parts makes it possible to transmit a satisfactorily large resilient force to each of the brushes II and I2 while permitting the use of a relatively thin and light rotor block construction and a minimum number of parts. Additionally, the arrangement described is capable of effecting a relatively equal pressure on each of the contact brushes at all times. The sliding contacts between yoke 30 and the caps 20 of the contact brushes provides suitable electrical contact between the same and the pin and slot connections 23 and 3| prevent any endwise movement of the yoke 30 from applying a tilting force to the brushes which would cause the same to become bound or stuck in their guide bushings 27. The contact brushes are thus relatively free to move with a reciprocating motion in the bushings 21 and the same may be removed from the rotor block for replacement or reconditioning with the utmost facility.

When the rotor is disassembled from the distributor or other unit of which it is designed to form a part, the contact brushes assume the positions illustrated in Fig. 2 of the drawings, the same being positively limited against movement in one direction by the shoulders 22 which engage bushings 21 or the rotor block, as the case may be, and said brushes are resiliently held against movement out of the rotor block in the other direction by spring 33 which remains under tension and transmits pressure to the contact brushes through the yoke 38. When the rotor 10 is mounted in operating position in a distributor or similar unit the same will be secured to its driving shaft so that the contact brushes will engage a contact ring or segments as the case may be under resilient pressure. For example, the contact brushes II and I2 will be moved upwardly, as viewed in Fig. 2, thereby moving yoke 30 upwardly and placing spring 33 under greater tension. When the structure is rotated with the brushes and parts in the positions last mentioned,

segments and are yieldably free to reciprocate relative to the rotor block [0 and relative to each other. The spring and yoke combination being adapted to apply a relatively equal pressure to each of the brushes at all times.

There is thus provided a novel electrical apparatus adapted for use as an ignition distributor rotor which embodies simplified means for maintaining a pair of electrically connected contact brushes in operative position during operation and for insuring comparatively equal pressure on each brush of the pair. Said means functions further as electrically conductive means connecting the brushes and as means to yieldably retain the brushes in the rotor when the latter is removed from the distributor or other unit of which it may be a part. Additionally, in the novel construction hereby provided the parts may be assembled without permanent connections therebetween so that the assembly time and manufacturing costs are substantially reduced. The latter feature also facilitates the replacement and repair of the various parts while providing a desirable freedom or relative movement thereof during operation. The novel construction and arrangement also substantially eliminates any danger of laterally binding or sticking of the brushes during rotor operation.

Although only one embodiment of the invention is illustrated in the accompanying drawings and described in the foregoing specification, it is to be expressly understood that the same is not limited thereto or to the specific use thereof in connection with an ignition distributor unit for internal combustion engines. Various changes in addition to those mentioned above and particularly changes in the design and arrangement of the parts illustrated may be made without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

What is claimed is:

1. In a device of the class described, a block comprising insulating material having a pair of spaced openings extending therethrough, a conducting brush slidably mounted in each of said openings, corresponding ends of said brushes projecting from one face of said block, means on said brushes and engageable with the other face of said block to limit the movement of said brushes into said block from said other face thereof, said means being constituted by an electrically conductive member on each brush comprising a cap having a sphere-like surface and. a fiat surface engaging the other end of the brush, a shank extending from said flat surface and having threaded engagement with a tapped recess in the brush and a pin projecting axially from said sphere-like surface of said cap, a rigid electrically conductive member bridging said other ends of said brushes and having longitudinally extending slots near the ends thereof for loosely receiving said pins, and a coil spring under tension having one end thereof anchored in said block between said, openings and connected at its other end to said bridging member, whereby said brushes are electrically connected by said bridging member and resiliently held in said block by said coil spring.

2. In a device of the class described, a member comprising insulating material having a pair of spaced openings extending therethrough, a conducting brush slidably mounted in each of said openings, corresponding end portions of said brushes projecting from one face of said member, stop means for limiting the extent of said projecting portions, said stop means comprising a metallic cap secured to the other end of each brush, each of said caps having a pin projecting axially therefrom, means for yieldably resisting movement of said projecting end portions into said member, said last named means including a yoke slidably engaging directly with said caps and having longitudinally extending slots near the ends thereof for loosely receiving said pins and resilient means connected between the longitudinal center of said yoke and said member.

3. A device as defined in claim 2 wherein each of said brushes has a threaded recess in said other end thereof and said cap has a threaded shank in threaded engagement with said recess.

4. A device as defined in claim 2 wherein said yoke consists of an elongated sheet metal bar which is arc-shaped in transverse section for rigidity.

5. A device as defined in claim 4 wherein said caps have segmental sphere-like surfaces for engagement with said arcuate yoke, the engaging surfaces of said yoke and caps having similar contours.

6. In a device of the class described, an electrically conductive brush adapted to be slidably mounted in a rotatable member and comprising a body of electrically conductive material, such as carbon, said body having a threaded recess in one end thereof, and a metallic cap having a shank threadedly received by said recess and an enlarged head portion which radially overhangs the body, said head portion having a segmental sphere-like surface with an axially extending pin projecting from the crest of said surface.

7. In a device of the class described, an electrically conductive brush adapted to be slidablby mounted in a rotatable member and comprising a body portion slidable in an opening in said member and a cap portion at one end of and overhanging said body portion, said cap portion having a segmental sphere-like surface with an axially extending pin projecting from the crest of said surface.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,115,069 Hall Apr. 26, 1938 2,515,234 Knudson July 18, 1950 FOREIGN PATENTS Number Country Date 642,622 Great Britain Sept. 6, 1950 

